1. Field of the Invention
The present invention relates to a fabrication method of a lead component and more particularly, to a fabrication method of a plastic-molded lead component serving as a connector, a coupler, and so on, which has aligned leads protruding from a molding plastic and which is used for electrically connecting the component to the outside.
2. Description of the Prior Art
A conventional lead component of this sort is shown in FIG. 3.
As shown in FIG. 3, this lead component 119 has electrically-conductive leads 102 molded by a molding plastic, i.e., a plastic tie-bar 118. The tie bar 18 has a shape of a rectangular parallelepiped. The leads 102 are fixed by and buried in the tie-bar 118 to penetrate the same.
Protruding parts of the leads 102 from one side of the tie bar 118 are aligned at a fixed pitch and extend outward in parallel to one another. Protruding parts of the leads 102 from the opposite side of the tie bar 118 are also aligned at the same pitch and extend outward in parallel to one another.
The protruding parts of the leads 102 at one side of the plastic tie-bar 118 are electrically connected to some leads of an electronic device/element or terminals of a circuit board on which electronic devices/elements are mounted, respectively. The protruding parts of the leads 102 at the opposite side of the tie bar 118 are used for electrically connecting the electronic device/element or the circuit board to the outside circuitry.
A fabrication method of the conventional lead component 119 shown in FIG. 3 is explained below with reference to FIGS. 1 and 2.
First, as shown in FIGS. 1 and 2, upper and lower molds 114 and 115, each of which is made of a metal such as stainless steel, are prepared. On the other hand, a pair of gripping jigs 117, which are made of a metal such as stainless steel, are prepared.
The upper mold 114 has V-shaped grooves 116A for aligning metal wire pieces 102' to be used for the leads 102 on its lower surface. The grooves 116A are aligned at the same pitch as that of the leads 102 in parallel to one another.
Similarly, the lower mold 115 has V-shaped grooves 116B for aligning the metal-wire pieces 102' on its upper surface. The grooves 116B are aligned at the same pitch as that of the leads 102 in parallel to one another.
The pair of gripping jigs 117 usually have no grooves on their inner surfaces.
Next, the ends of the wire pieces 102' are placed on the lower mold 115 to be located in the respective grooves 116B. Then, the upper mold 114 is coupled with the lower mold 115 in such a way that the V-grooves 116A of the upper mold 114 are coupled with the corresponding V-grooves 116B of the lower mold 115, thereby forming aligning cavities. Thus, the ends of the wire pieces 102' are held to be aligned along a straight line by the aligning cavities, as shown in FIGS. 1 and 2.
Subsequently, the protruding parts of the wire pieces 102' from the coupled molds 114 and 115 are gripped at their opposite ends to the molds 114 and 115 by the pair of gripping jigs 117, as shown in FIG. 2. The pair of gripping jigs 117 are apart from the molds 114 and 115.
Then, while applying tension to the wire pieces 102' with the use of the molds 114 and 115 and the pair of jigs 117, the aligned wire pieces 102' are molded by a molding plastic (not shown) at a location between the coupled molds 114 and 115 and the pair of jigs 117 through popular plastic-molding processes. Thus, the wire pieces 102' are fixed by the molding plastic, i.e., the plastic tie-bar 116 at an approximately center of the wire pieces 102', as shown in FIG. 2.
Finally, the wire pieces 102' are cut at each side of the tie bar 118 to thereby separate the coupled molds 114 and 115 and the pair of jigs 117 from the wire pieces 102'. As a result, the remaining wire pieces 102', i.e., the leads 102, are fixed by the tie bar 118 and protrude from each side of the tie bar 118.
Thus, the conventional plastic-molded lead component 119 as shown in FIG. 3 is fabricated.
Although the conventional plastic-molded lead component 119 has a single row of the leads 102 at each side of the molding plastic 118, it may have a plurality of parallel rows of the leads 102.
Another conventional lead component of the above sort is shown in FIG. 4, which serves as an agglomerate generator of a particulate substance and is applicable to a printer head. This conventional component was disclosed in the Japanese Publication No. 7-502218 of the PCT application No. PCT/AU92/00665 published in March 1995.
As shown in FIG. 4, an electrically-conductive body 220 has a tapered shape. An electrically-conductive feeding tube 221 is provided in the body 220 to be electrically connected to the body 220. The feeding tube 221 has a peak at its end located at the thin side of the body 220. This peak of the tube 221 has a small radius of curvature, which is termed an ejection point 222.
The opposite end of the feeding tube 221 to the ejection point 222 is connected to a liquid feeding system 223 (not shown). This liquid feeding system 223 is capable of feeding a specific liquid containing ink particles under a constant pressure. Excessive portions of the supplied liquid are extracted to the outside through an extracting path 224A and an extracting tube 224B each provided in the body 220. The opposite end of the extracting tube 224B to the ejection point 222 is connected to a liquid extracting system 225 (not shown) located outside the body 220.
A voltage source 226 is provided outside the body 220. The voltage source 226 supplies a suitable voltage to the body 220 as necessary and consequently, the suitable voltage may be applied to the feeding tube 221. The liquid containing the ink particles is fed into the feeding tube 221 by the liquid feeding system 223 and then, it travels through the tube 221 toward the ejection point 222.
The electric field generated by the applied voltage is the highest at the ejection point 222. Therefore, the liquid containing the ink particles is ejected toward a printing medium 213 placed apart from the ejection point 222. The ejected liquid travels to the medium 213 in a direction perpendicular to the medium 213. Thus, the ejected liquid containing the ink particles are printed on the medium 213.
Still another conventional lead component of the above sort is shown in FIG. 5, which was disclosed in the above Japanese Publication No. 7-502218 of the PCT application No. PCT/AU92/00665.
As shown in FIG. 5, this conventional lead component is a variation of the agglomerate generator shown in FIG. 4, and has the same configuration as that of the above conventional component in FIG. 4 other than that a plurality of ejection points are provided. Therefore, the explanation about the same configuration is omitted here by adding the same reference numerals to the same or corresponding elements in FIG. 5 for the sake of simplicity.
In FIG. 5, a blade 227 is fixed to and electrically connected to the thin-side end of the tapered body 220. The blade 227 protrudes from the facing thin-side end of the body 220.
Here, the body 220 has three electrically-conductive strips 229 extending from the thick-side end of the body 220 to the thin-side end thereof. The strips 229 are electrically connected to the corresponding voltage sources 226 provided outside the body 220. The strips 229 are electrically insulated from one another by an insulating material 228 provided in the body 220.
Similarly, the blade 227 has three electrically-conductive strips 231 extending along the same direction as that of the strips 229 of the body 220. The strips 231 are electrically connected to the corresponding strips 229. The strips 231 are electrically insulated from one another by an insulating material 230 provided on the blade 227.
The peaks of the strips 231, which protrude from the insulating material 230 of the blade 227, serve as the ejection points 222, respectively.
With the conventional plastic-molded lead component shown in FIG. 1, the V-grooves 116A and 116B of the upper and lower metal molds 114 and 115 need to be formed by the known machining technique or known laser processing technique. Therefore, the following problems will occur.
Specifically, if the leads 102 are aligned at a fine pitch of approximately 100 .mu.m or less, the V-grooves 116A and 116B are necessarily formed to be aligned at the same fine pitch. However, these grooves 116A and 116B cannot be uniformly formed with the use of the conventional machining or laser processing technique. This is because (i) the dimensional accuracy of the machining tools such as drills, (ii) the machining or laser processing accuracy, and (iii) the process control technique accuracy are all poor.
If the grooves 116A and 116B have the non-uniform top-end width, bottom-end angle, and/or depth, the positional deviation or shift of the aligned leads 102 by the molds 114 and 115 will be generated.
Thus, due to the dimensional and aligning accuracy limits of the grooves 116A and 116B of the upper and lower molds 114 and 115, the obtainable pitch of the grooves 116A and 116B is approximately 1 mm at the minimum. This means that the obtainable pitch of the leads 102 is approximately 100 .mu.m at the minimum. Any finer pitch is unable to be realized.
Further, since the grooves 116A and 116B are successively formed one by one by the machining or laser technique, not only a lot of time is necessary for completing the grooves 116A and 116B but also the fabrication cost becomes high.
With the conventional plastic-molded lead components shown in FIGS. 4 and 5 to decrease the printing dot size for higher resolution, the ejection points 222 need to be aligned at a fine pitch on the body 220. This requires the patterning process of the electrically-conductive strips 229 and 231 using radiation exposure and development processes.
In this case, there arises a problem that the formation processes of the strips 229 and 231 are complicated and the fabrication cost is high.